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Intestinal infections

 
, medical expert
Last reviewed: 05.07.2025
 
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Intestinal infections are a group of diseases that are united by a single route of transmission of the pathogen, as well as its localization in the body - the intestines.

Pathogens of intestinal infections can remain outside the intestines for a long time. Getting out with feces, pathogenic bacteria remain in water or soil and, under certain conditions, penetrate the body of a new "host".

Infection usually occurs through the consumption of unwashed vegetables, fruits, berries, or poor quality food or water.

Since the main environment for the vital activity of pathogenic bacteria is the intestines, the first sign of such diseases is diarrhea, and therefore, the WHO classifies all infections of this type as diarrheal diseases.

ICD-10 code

In the international classification of diseases, intestinal infections are coded A00 - A09. This group of diseases includes amebiasis, typhus (paratyphus), cholera, shegellosis, bacterial poisoning, tuberculous enteritis, salmonella infections, diseases caused by parasitic protozoa, viruses (influenza with gastrointestinal tract involvement is excluded).

Statistics

According to the World Health Organization, intestinal infections annually cause the death of more than two million people worldwide, most of whom are children. Diseases of this group are widespread and in some countries child mortality from intestinal infections accounts for up to 70% of the total mortality of children under 5 years of age.

Epidemiology

As already mentioned, intestinal infections spread from sick people or carriers of dangerous bacteria to healthy people. An infected person is dangerous from the beginning of the disease, as the condition improves, the infectiousness also decreases, however, in some cases, a person can be dangerous for a long time.

During the research it was proved that the release of pathogenic bacteria can remain after recovery, which occurs due to pathological processes in the intestine. When a person stops spreading the infection can be determined only after a bacteriological study.

Patients with latent forms of the disease are of great importance in the spread of the infection, since such people are not diagnosed and they continue to be in the group, spreading dangerous bacteria.

Also, small children who do not yet have basic hygiene skills and who suffer from latent forms of intestinal infections can easily infect the external environment and objects.

Newborns often get the disease from their mothers.

Carriers of pathogenic bacteria are quite rare, however, such people also contribute to the spread of infection.

Of all the types of intestinal infections, salmonellosis can be singled out, since animals also participate in its spread. Most often, the disease is transmitted from domestic animals (cows, dogs, cats, horses, etc.), as well as from rodents.

Birds, especially waterfowl, are considered the main source of infection. Salmonella bacteria are present not only in the organs, as in most animals, but also in the shell and contents of eggs. At the same time, birds remain carriers of dangerous bacteria longer than animals.

Intestinal infection can occur both as a single case and in the form of epidemic outbreaks, and the disease can reach large-scale proportions, for example, as in the case of cholera. In the summer-autumn period, a high level of most intestinal infections is observed, in the winter period the level of viral diarrhea increases.

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Causes of intestinal infection

Intestinal infections begin to develop when the pathogen enters the body (intestine). As already mentioned, the pathogen can enter the body when drinking contaminated water (tap, spring, etc.), as well as with unwashed vegetables, fruits, etc.

Pathogenic microorganisms actively multiply outside the body, especially in warm and humid conditions. Products stored outside the refrigerator, especially meat and dairy products, pose a great danger in this regard.

In the summer, intestinal diseases are more dangerous, since in the heat food spoils faster, especially meat and fish, and various insects can carry the infection from contaminated feces. The incubation period of intestinal infection

The incubation period is the period from the moment pathogenic microorganisms enter the intestine until the first symptoms of the disease appear. In other words, this is the latent period of the disease, when the infection has already occurred, but there are no signs of the disease.

Gastrointestinal infections most often manifest themselves 12 to 36 hours after infection; in some cases, the latent period can last up to 12 days.

There are three main ways of transmitting intestinal infections: through food, water and household contact.

Most often, intestinal infection is transmitted through food products contaminated with microorganisms or that have undergone insufficient heat and hygienic processing. The source of the disease can be both people and animals (cattle and small cattle, poultry, rodents, etc.). From the carrier, the infection can get into milk (dairy products), eggs, fruits, vegetables.

Waterborne transmission of the disease is a little less common. Infection mainly occurs when drinking poor quality water. This usually happens as a result of a burst water or sewer pipe.

During household contact, the infection can spread from the carrier through dirty hands or various objects (towels, toys).

The causative agents of intestinal infections are pathogenic bacteria that enter the environment with feces and contaminate food or water. There are also bacteria that are excreted with urine or vomit, such as bacteria of food poisoning or cholera.

The main source of infection is an infected person or a carrier of a pathogenic infection. A carrier of bacteria is a nearly healthy person whose body contains pathogenic microorganisms that are released into the external environment.

Typically, carriers of the infection are people with weakened immune systems, who have had an intestinal infection, or who have chronic gastrointestinal or gallbladder diseases.

Infections can also be spread by healthy people whose bodies have been exposed to pathogenic microbes, but they have taken root in them and do not cause harm to their “host”.

Faeces with pathogenic microorganisms can become a source of infection. Quite often, the disease spreads through dirty hands and objects - if the hands of a sick person or carrier of an infection are contaminated with feces, then everything he touches becomes a source of infection. If a healthy person touches contaminated objects, then he can transfer pathogenic bacteria to food and become infected. Therefore, experts urge to wash your hands as often as possible, especially after using the toilet.

Intestinal infections can be spread through toys, handrails on public transport, handles on shopping baskets in supermarkets, etc.

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Symptoms of intestinal infection

The symptoms of intestinal infections depend on the type of pathogen, but there are general signs that can help you understand the cause of poor health: weakness, poor appetite, abdominal pain.

The action of pathogenic microorganisms in the intestines does not manifest itself immediately; when bacteria or viruses enter the gastrointestinal tract, they undergo an “incubation period,” which can last from 10 to 50 hours.

The appearance of the first signs of the disease depends on the activity of pathogenic microflora in the body; on average, the first symptoms appear 12 hours after infection.

Minor malaise at first is replaced by severe abdominal pain, vomiting, frequent loose stools. In addition, the temperature rises, chills, increased sweating and other signs of fever appear, loss of consciousness is possible.

These symptoms indicate severe intoxication of the body due to the activity of pathogenic bacteria; frequent vomiting and loose stools lead to dehydration of the body, which leads to irreversible consequences (impaired kidney function, changes in the cardiovascular system).

Intestinal infections in children and the elderly can be fatal.

The intestinal infection syndrome manifests itself in the form of fever, weakness, pale skin (with some infections against the background of high temperature), decreased blood pressure, in severe cases of the disease, cold hands and feet are observed, in children under one year of age, intoxication can cause neurological disorders.

In addition, diarrhea and vomiting that occur with intestinal infections can lead to dehydration.

Depending on the pathogen, intestinal infections may cause a rise in temperature (37ºC and above).

Some infections occur without a rise in temperature (cholera) or with a slight short-term increase (staphylococcus).

Diarrhea almost always accompanies intestinal infections. After infection, diarrhea may appear after several hours (in case of food poisoning) or days (in case of bacterial infection).

Some bacteria can be life-threatening, so when the first signs of an intestinal disease appear, you should immediately consult a doctor, especially if the stool is very watery or contains blood.

Acute intestinal infections are a group of diseases that mainly affect the intestines. The cause of infection are pathogenic bacteria and viruses. In most cases, such diseases provoke severe food poisoning, which is accompanied by diarrhea, vomiting, fever, and abdominal pain.

If symptoms of acute intestinal infection appear, you should immediately seek medical help and undergo a course of treatment in a hospital.

Where does it hurt?

The course of intestinal infection

Different types of intestinal infections have different symptoms and can progress differently, for example, rotavirus infections are mild, causing not only loose stools, vomiting, but also cold symptoms, with dysentery, loose stools with blood impurities appear, the disease usually progresses severely, with severe abdominal pain, with salmonellosis, the stool is dark green.

But in a number of cases, the causative agent of the infection remains unknown, and doctors indicate in the diagnosis that the etiology of the disease has not been established.

Almost all intestinal infections proceed in the same way, where one period of the disease gradually gives way to another:

  • incubation period – the time from the onset of infection to the moment the first symptoms appear, this period depends on the individual characteristics of the organism and can last from several hours to several days. At this stage, the first signs of intestinal infection may be lethargy, rapid fatigue.
  • acute period – lasts from 1-2 days to two weeks. This period is characterized by the appearance of diarrhea, abdominal pain, vomiting, and fever.

It is worth noting that some people carry the infection with one main symptom, i.e. only with vomiting or only with diarrhea, and the disease can also occur with or without fever.

  • recovery period – begins after diarrhea, diarrhea and other signs of the acute stage of the disease stop. Recovery of the body can take a long time (up to several years) if the treatment was ineffective or completely absent. During this period, the body is especially susceptible to viruses and bacteria, there is a high probability of re-infection with an intestinal infection or cold. The course of the disease in the acute and recovery stages depends on the pathogen, the number of bacteria or viruses that entered the body, the person's condition before infection (weakened immunity, concomitant diseases, intestinal microflora disorder, etc.), as well as on timely treatment.

Complications of intestinal infections

If the disease does not receive the necessary treatment, then a state of shock may develop, caused by dehydration or waste products of pathogenic flora.

In addition, intestinal infections can provoke inflammation in the abdominal cavity, intestinal bleeding, disruption of intestinal microflora, heart failure, and joint inflammation.

Allergy after an intestinal infection can occur as a result of the immune system's reaction to bacteria or viruses. This usually manifests itself as a skin rash.

Viral infections can increase intestinal permeability, which increases the risk of developing food allergies in the future.

Allergic reactions may also occur while taking medications, especially after taking antibiotics.

The recovery period after an intestinal infection can take a long time, the digestive system is disrupted and it takes a certain amount of time to restore all functions. To help the body, enzyme preparations are prescribed that improve digestion, prebiotics and probiotics, which contain beneficial bacteria to normalize the intestinal microflora.

Weakness is one of the symptoms of an intestinal infection. The malaise is caused by the action of toxins that poison the entire body and can persist for some time after the main symptoms of the disease (vomiting, diarrhea, fever) have disappeared. Usually, the recovery period with proper and timely treatment takes several days. Other factors are also important, such as the state of the immune system, dysbacteriosis, and concomitant diseases, which can increase the recovery period of the body after an illness.

Weakness after an infection may be associated with prolonged vomiting, diarrhea, and fever, which deprive the body of important nutrients and disrupt metabolic processes.

Vomiting often occurs with intestinal infections; it develops due to disruption of the gastrointestinal tract and poisoning of the body with microbial toxins.

Vomiting appears during the acute period of the disease, as the patient recovers, this symptom gradually disappears, and during the period of recovery of the body, as a rule, vomiting does not bother a person.

The recurrence of a symptom, especially against the background of weakness, fever, diarrhea, may indicate a recurrence of the disease or a new infection.

This situation often occurs in hospitals, and young children who have poor personal hygiene and who come into contact with other children in the hospital who are sick with other infections are especially vulnerable.

Abdominal pain during intestinal infection is caused by pathogenic microorganisms that have entered and are actively multiplying in the intestines. Depending on the pathogen, the pain can be of varying intensity and have a different character - aching, spasms, sharp, etc.

After recovery, abdominal pain may persist for some time, which is associated with the consequences of bacterial activity and the restoration of normal functioning of the gastrointestinal tract.

Often the pain is accompanied by loose stools (1-2 times a day), which is associated with the inadequate functioning of the digestive system after an infection. This condition should not cause concern, but if other symptoms appear (fever, frequent loose stools, nausea, vomiting), you should consult a doctor.

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Diagnosis of intestinal infection

If an intestinal infection is suspected, the doctor first determines the time of the first symptoms, possible risk factors that could have provoked the disease (swimming in bodies of water, poor quality water, spoiled food, contact with animals or birds, etc.). Also, concomitant diseases that could increase the risk of contracting an intestinal infection (alcoholism, HIV, etc.) are determined.

The symptoms of intestinal infection are common to a number of other diseases, so it is impossible to make an accurate diagnosis during the initial examination and additional tests are prescribed (blood, urine, stool tests, bacterial culture), which will help to identify the causative agent of the infection and determine an effective course of treatment.

An analysis for intestinal infections is necessary to identify the pathogen and select an antibiotic that can fight the infection. Usually, without an analysis, the process of treating intestinal infections is protracted, since the drug sensitivity of bacteria to antibiotics or other drugs may differ in different patients.

As already mentioned, intestinal diseases can be viral or bacterial in nature; it is quite difficult to make a correct diagnosis and prescribe effective treatment based on symptoms.

For this reason, tests are important in intestinal infections.

Microbiological analysis of feces reveals the causative agent of intestinal infection. This analysis is also called sowing, it is based on the study of feces under a microscope with subsequent sowing. It is not always possible to determine the type of infection under a microscope, since the sample being studied may contain an insignificant amount of bacteria, so after this, a fecal sample is sown in a special device that maintains the optimal temperature for the reproduction of bacteria. At this stage, when active growth of bacterial colonies begins, microorganisms inhabiting the intestines are identified.

After a few days, the pure culture sample is again examined under a microscope to accurately identify pathogenic bacteria.

If pathogenic microorganisms are found in the stool, an analysis of bacterial sensitivity to antibacterial drugs is carried out. At this stage, various groups of antibiotics are introduced into the bacterial colony and it is noted how quickly and in what quantities the bacteria die after exposure to a particular drug.

The test results indicate the infectious agent and other bacteria found in the intestines, as well as the type of antibiotics to which the pathogenic microorganisms are sensitive.

PCR (polymerase chain reaction) analysis allows you to determine the type of infection by a small fragment of RNA or DNA of pathogenic microorganisms in any fluid produced by the human body. This study allows you to determine both bacterial and viral infections.

PCR analysis can be quantitative and qualitative. Quantitative testing identifies the number of pathogens in the stool, while qualitative testing identifies the type of infectious agent.

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Differential diagnostics

Differential diagnosis excludes diseases that do not match the symptoms, which ultimately allows a diagnosis of one possible disease to be made.

There are various systems and programs that perform differential diagnostics, both complete and partial.

The main, but not exclusive symptom of intestinal infection is diarrhea; it is differential diagnostics that allows us to exclude errors and incorrect treatment.

Before making a diagnosis, the specialist determines the patient’s age, the nature and frequency of bowel movements, vomiting, the intensity of pain, and also takes into account the seasonality.

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Prevention of intestinal infection

To prevent intestinal infections, experts recommend following a few simple rules, first of all, you need to wash your hands with soap as often as possible (after coming home, going to the toilet, peeling vegetables or cutting meat, working in the garden or vegetable garden, before eating, etc.).

If you are in places where access to water is difficult, you need to stock up on special antibacterial agents (wet wipes, sprays, etc.).

You cannot drink water from the tap, spring, river, street pump, etc.

Before consumption, you need to wash fruits, vegetables, berries well. When buying melons, watermelons, you need to give preference to whole fruits, in cut, wrinkled, cracked places harmful microorganisms quickly multiply.

Buy meat, milk and fermented milk products only in stores. If you buy raw milk at the market, you must boil it.

During the trip, food should be stored in separate bags.

You cannot swim in prohibited areas; it is important not to swallow water while swimming.

Do not allow insects, which are the main carriers of dangerous infections, to sit or crawl on food.

Quarantine is carried out to prevent further spread of infection among children in child care institutions, employees, etc. Such measures help stop the spread of dangerous infections, and quarantine can be introduced within a kindergarten, school, any institution, as well as at the state level with the closure of borders not only for the entry or exit of citizens, but also for the import or export of products.

Prognosis of intestinal infection

Early detection of infection and proper therapy contribute to a full recovery without serious complications. It should be remembered that after an illness, the body's defenses are weakened and it is defenseless against viruses and infections, which requires additional precautions (avoid hypothermia, do not expose yourself to nervous shocks, stress, etc.).

In severe cases of the disease, toxic shock syndrome, pulmonary edema, renal or cardiac failure, DIC syndrome, etc. are possible.

Intestinal infections are the most common diseases in the world; pathogenic bacteria pose a particular danger in the summer season, when favorable conditions arise for the active reproduction of pathogenic microflora.

As a rule, the acute period of the disease passes in a few days, provided that the treatment is correct (drinking plenty of fluids, taking enterosorbents and drugs to restore water-electrolyte balance). It is worth noting that taking antiemetic and antidiarrheal drugs for intestinal infections is prohibited, as this will stop the body from cleansing itself of pathogenic microorganisms and toxins and lead to even greater intoxication.

If there is no improvement after 2-3 days, you should seek medical help and undergo a full examination in case of infection with dangerous infections.

If not treated correctly, relapses often occur, and the disease can become chronic, and the person will become dangerous to others.

It is necessary to immediately consult a doctor if diarrhea occurs in children under one year of age, if there is severe vomiting, when a person cannot even take a sip of water without a gag reflex, if there is urinary retention, blood appears in the stool, a high temperature that does not decrease with the use of antipyretics, or if there is loss of consciousness.

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